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Biomedical subjects

M M Adams

Publications and source records attributed to M M Adams.

At least 37 records · Page 2Linked to original sources
PubMed1997

Constructing reproductive histories by linking vital records.

Certificates of 1,449,287 live births and fetal deaths filed in Georgia from 1980 through 1992 were linked to create chronologies that, excluding induced abortions and ectopic pregnancies, constituted the reproductive experience of individual women. The authors initially used a deterministic method (whereby linking rules were not based on probability theory) to link as many records as possible, knowing that some of the linkages would be incorrect. They subsequently used a probabilistic method (whereby evaluation of linkages was developed from probability theory) to evaluate each linkage, and they broke those that were judged to be incorrect. Of the 1.4 million records, 38% did not link to another record. From the remaining records, 369,686 chains of two or more events were constructed. The longest chain included 12 events. Of the chains, 69% included two events; 22% included three events. Longer chains tended to have lower scores for probable validity. The probability-based evaluation of chains affected 3.0% of the records that had been in chains at the end of the deterministic linkage. A greater percentage of records in longer chains were affected by the evaluation. Unfortunately, the small subset of records that were the most difficult to link tended to overrepresent groups with the greatest risk of adverse pregnancy outcomes. Researchers contemplating a similar linkage can anticipate that, for the majority of records, linkage can be accomplished with a relatively straightforward, deterministic approach.

Adolescent↗
PubMed1997

Patterns of prenatal care initiation in Georgia, 1980-1992.

OBJECTIVE: To determine whether characteristics in a woman's first pregnancy were associated with the trimester in which she initiated prenatal care in her second pregnancy. METHODS: Data for white and black women whose first and second pregnancies resulted in singleton live births between 1980 and 1992 were obtained from Georgia birth certificates (n = 177,041). Adjusted relative risks (RRs) for early prenatal care in the second pregnancy were computed by logistic regression models that included trimester of prenatal care initiation, infant outcomes, or maternal conditions in the woman's first pregnancy as the exposure and controlled for maternal age, education, child's year of birth, interval between first and second pregnancy, presence of father's name on the birth certificate, and the interaction between prenatal care and education. Models were stratified by race. RESULTS: Women of both races who initiated prenatal care in the first trimester of their first pregnancies were more likely than those with delayed care to initiate prenatal care in the first trimester of their second pregnancies (RR = 1.25 and 1.63 for white and black women educated beyond high school, respectively). Both white and black women who delivered a baby with very low birth weight (RR = 1.06 and 1.15, respectively) or who suffered an infant death (RR = 1.09 and 1.31, respectively) in their first pregnancies were more likely than those who did not experience these events to begin prenatal care in the first trimester of their second pregnancies. CONCLUSION: Women with some potentially preventable adverse infant outcomes tend to obtain earlier care in their next pregnancy. Unfortunately, women who delayed prenatal care in their first pregnancy frequently delay prenatal care in their next.

Female↗
PubMed1997

Prenatal smoking in two consecutive pregnancies: Georgia, 1989-1992.

OBJECTIVE: To explore the patterns of prenatal smoking among women whose first and second pregnancies ended in live births. METHODS: We used population-based data to explore prenatal smoking among 14,732 white and 8968 black Georgia residents whose first and second pregnancies ended in live births during 1989-1992. Smoking status was obtained from birth certificates linked for individual mothers. Because of demographic differences, we analyzed white and black women separately. RESULTS: Approximately 15% (2253) of white women and 4% (318) of black women smoked during their first pregnancy. Of those smokers, 69% (1551) of white women and 58% (184) of black women also smoked during their second pregnancy. For both white and black nonsmokers during the first pregnancy, low education was the most significant predictor of smoking during the second pregnancy, after adjusting for consistency of the father's name on the birth certificate, prenatal care, birth interval, mother's county of residence, and birth outcome. CONCLUSIONS: The prevalence of smoking in this study may be low because of underreporting of prenatal smoking on birth certificates. The majority of women who smoked during their first pregnancy also smoked during their second, suggesting that these women exposed their first infant to tobacco smoke both in utero and after delivery. Practitioners should offer smoking cessation programs to women during, as well as after, pregnancy. Pediatricians should educate parents on the health risks to young children of exposure to environmental tobacco smoke and refer smoking parents to smoking cessation programs.

Adolescent↗
PubMed1997

The relationship of interpregnancy interval to infant birthweight and length of gestation among low-risk women, Georgia.

To examine the association between interpregnancy interval and low birthweight (< 2500 g), preterm delivery (< 37 weeks' gestation), and inadequate fetal growth, we studied a population-based sample of 23,388 white and 4885 black women at low risk for adverse pregnancy outcomes who delivered their first and second infants in Georgia from 1980 to 1992. We used fetal death and livebirth certificates. The interpregnancy interval was the time from delivery to the woman's next conception. For each pregnancy outcome, we stratified by race and used logistic regression to assess the association between interpregnancy interval and outcome, while controlling for confounders. Intervals < 6 months were observed for 3.7% of white women and 7.0% of black women and intervals > or = 48 months were seen for 16.8% of white women and 24.8% of black women. Results from logistic regression showed that, for both races, interpregnancy interval was associated with low birthweight and preterm delivery. Nearly all of the increased risk occurred in intervals < 6 months or > or = 48 months. The magnitude of the increase in risk associated with these intervals ranged from modest to moderate and was similar for black and white women. Because short interpregnancy intervals are rare and are weak risk factors among low-risk women, efforts to lengthen interpregnancy intervals are unlikely to reduce substantially their rates of adverse pregnancy outcomes.

Adult↗
PubMed1997

Evaluation of reproductive histories constructed by linking vital records.

We used 1.4 million fetal death and birth certificates filed in Georgia between 1980 and 1992 to construct 369,686 chains of two or more reproductive events occurring to the same woman. We evaluated these chains using both information on the certificates and information independently collected in interviews with 1311 women. Overall, 86.6% of the chains had the expected number of events, based on the certificate's information about previous pregnancies. Seventy-nine per cent of the chains had the expected number of events based on the maternal interviews. Consistency between the observed number of events in the chain and the number expected, based either on data from the certificates or from the maternal interviews, was greatest for chains with two or three events. Mothers born in Georgia were more likely to have complete chains than mothers born elsewhere. Among the 551,391 non-linked certificates, 48.7% were the mother's first birth, 40.2% were second or higher-order births to women whose previous pregnancy occurred before 1980, and 11.1% were second or higher-order births to women whose previous pregnancy occurred after 1980. Fetal death and livebirth certificates can be linked to construct pregnancy histories with reasonably low levels of underlinkage and overlinkage.

Adult↗
PubMed1996

Neurofilament protein is differentially distributed in subpopulations of corticocortical projection neurons in the macaque monkey visual pathways.

Previous studies of the primate cerebral cortex have shown that neurofilament protein is present in pyramidal neuron subpopulations displaying specific regional and laminar distribution patterns. In order to characterize further the neurochemical phenotype of the neurons furnishing feedforward and feedback pathways in the visual cortex of the macaque monkey, we performed an analysis of the distribution of neurofilament protein in corticocortical projection neurons in areas V1, V2, V3, V3A, V4, and MT. Injections of the retrogradely transported dyes Fast Blue and Diamidino Yellow were placed within areas V4 and MT, or in areas V1 and V2, in 14 adult rhesus monkeys, and the brains of these animals were processed for immunohistochemistry with an antibody to nonphosphorylated epitopes of the medium and heavy molecular weight subunits of the neurofilament protein. Overall, there was a higher proportion of neurons projecting from areas V1, V2, V3, and V3A to area MT that were neurofilament protein-immunoreactive (57-100%), than to area V4 (25-36%). In contrast, feedback projections from areas MT, V4, and V3 exhibited a more consistent proportion of neurofilament protein-containing neurons (70-80%), regardless of their target areas (V1 or V2). In addition, the vast majority of feedback neurons projecting to areas V1 and V2 were located in layers V and VI in areas V4 and MT, while they were observed in both supragranular and infragranular layers in area V3. The laminar distribution of feedforward projecting neurons was heterogeneous. In area V1, Meynert and layer IVB cells were found to project to area MT, while neurons projecting to area V4 were particularly dense in layer III within the foveal representation. In area V2, almost all neurons projecting to areas MT or V4 were located in layer III, whereas they were found in both layers II-III and V-VI in areas V3 and V3A. These results suggest that neurofilament protein identifies particular subpopulations of corticocortically projecting neurons with distinct regional and laminar distribution in the monkey visual system. It is possible that the preferential distribution of neurofilament protein within feedforward connections to area MT and all feedback projections is related to other distinctive properties of these corticocortical projection neurons.

Animals↗
PubMed1996

1H NMR investigation of the secondary structure, tertiary contacts and cluster environment of the four-iron ferredoxin from the hyperthermophilic archaeon Thermococcus litoralis.

The solution molecular structure of the four-iron ferredoxin (Fd) from the hyperthermophilic archaeon Thermococcus litoralis (Tl) has been investigated by 1H NMR spectroscopy. TOCSY and NOESY experiments in H2O, tailored to detect both weakly and strongly relaxed resonances, together with steady-state NOEs in both H2O and D2O, allowed the identification of 58 of the 59 residues, with one residue near the paramagnetic center undetected. It is shown that the contact shifted and strongly relaxed signals for all four cysteines ligated to the paramagnetic cluster can be assigned by standard backbone connectivities that do not require any assumptions about the tertiary structure. Secondary structural elements identified in Tl Fd are a three-stranded antiparallel beta-strand involving the termini of the protein, a double beta-strand (also antiparallel), two alpha-helices and four turns. The existence of a disulfide bridge between the nonligated cysteines is also proposed. Dipolar contacts observed in the NOESY maps and by steady-state NOEs between the ligated cysteines and the 'diamagnetic' protein matrix indicate that the overall folding pattern of Tl Fd is very similar to that of the 3Fe ferredoxin from the mesophilic bacterium Desulfovibrio gigas [Kissinger et al. (1991) J. Mol. Biol., 219, 693-723]. The influence of the paramagnetism of the cluster on the relaxation properties of the proton signals of nonligated residues near the cluster, as well as on the ligated cysteines, correlates well with the proximity to the cluster iron(s), as predicted from the crystal structures for homologous protons of other single-cluster ferredoxins. Finally, the potential role of the various identified structural factors in contributing to the hyperthermostability of this protein is discussed.

Amino Acid Sequence↗
PubMed1996

Trends in the percentage of women who received no prenatal care in the United States, 1980-1992: contributions of the demographic and risk effects.

OBJECTIVE: To determine if the increase in the percentage of women who received no prenatal care in the United States relative to 1980 (from 1.3% in 1980 to 2.2% in 1989 and 1.7% in 1992) was due to increasing risks of no care in subgroups of women or increasing percentages of births to women at high demographic risk of no care. METHODS: We analyzed U.S. birth certificates for the period 1980-1992. The annual adjusted odds of no prenatal care relative to 1980 were computed by logistic regression models that included year, maternal characteristics, and interactions of these characteristics with year. We also examined changes in the annual distributions of births by maternal characteristics. RESULTS: The risk of no prenatal care in most subgroups increased during the early 1980s, peaked in the late 1980s, and declined thereafter. For example, among black women, the adjusted risk of no care more than doubled from 1980 to 1989. Throughout the 1980s and into the 1990s, the percentage of births to women at high demographic risk of no care increased. This increase in the percentage of births to women at high demographic risk shows no sign of abating. CONCLUSIONS: During the 1980s, increasing risks in subgroups of women drove the increase in the crude rate of no prenatal care. Despite decreases in the risks of no care in the early 1990s, increasing percentages of births to women with high demographic risk for no care prevented a decrease in the crude rate to the 1980 level.

Black or African American↗
PubMed1995

Functional MRI evidence for adult motor cortex plasticity during motor skill learning.

Performance of complex motor tasks, such as rapid sequences of finger movements, can be improved in terms of speed and accuracy over several weeks by daily practice sessions. This improvement does not generalize to a matched sequence of identical component movements, nor to the contralateral hand. Here we report a study of the neural changes underlying this learning using functional magnetic resonance imaging (MRI) of local blood oxygenation level-dependent (BOLD) signals evoked in primary motor cortex (M1). Before training, a comparable extent of M1 was activated by both sequences. However, two ordering effects were observed: repeating a sequence within a brief time window initially resulted in a smaller area of activation (habituation), but later in larger area of activation (enhancement), suggesting a switch in M1 processing mode within the first session (fast learning). By week 4 of training, concurrent with asymptotic performance, the extent of cortex activated by the practised sequence enlarged compared with the unpractised sequence, irrespective of order (slow learning). These changes persisted for several months. The results suggest a slowly evolving, long-term, experience-dependent reorganization of the adult M1, which may underlie the acquisition and retention of the motor skill.

Adult↗
PubMed1995

The relationship between pregnancy intendedness and physical violence in mothers of newborns. The PRAMS Working Group.

OBJECTIVE: To determine if pregnancy intendedness is associated with physical violence, and to identify factors that modify this association. METHODS: Three to 6 months after delivery, we mailed a questionnaire to a population-based sample of 12,612 mothers of infants born during 1990 and 1991 in four states. We used multiple logistic regression to compute odds ratios. RESULTS: The state-specific prevalences (+/- standard error) of physical violence ranged from 3.8 +/- 0.5 to 6.9 +/- 0.8%; the prevalences of unwanted or mistimed pregnancies ranged from 36.9-46.3%. In each state, higher rates of physical violence were reported by women who had fewer than 12 years of education, lived in crowded conditions, participated in the Special Supplemental Food Program for Women, Infants, and Children, received no or delayed prenatal care, or were of races other than white, under 20 years old, or not married. Regardless of other attributes, women with unwanted or mistimed pregnancies reported higher rates of physical violence than women with intended pregnancies and accounted for 70% of women who reported physical violence. Overall, women with unwanted pregnancies had 4.1 (95% confidence interval 2.7-6.2) times the odds of experiencing physical violence than did women with intended pregnancies. This association was weaker for women with few social advantages than for those with more advantages. CONCLUSION: Physical violence toward women during the periconceptional and antenatal periods occurs in all sociodemographic groups. Women with unwanted or mistimed pregnancies are at an increased risk for violence by their partners compared with women with intended pregnancies.

Confidence Intervals↗
PubMed1995

Risk factors for preterm delivery in a healthy cohort.

To examine whether risk factors differed among subgroups of preterm (< 37 weeks of gestation) deliveries, we studied a cohort of 1,825 enlisted servicewomen who delivered from 1987 through 1990 at four U.S. Army medical centers. Preterm deliveries were classified by length of gestation (< 29 weeks, 29-32 weeks, 33-36 weeks) and clinical course [medical indication, idiopathic preterm labor, or preterm rupture of membranes (PROM)]. We abstracted medical records for information on age, race, army rank, marital status, gravidity, parity, the baby's sex, maternal prepregnancy height and weight, gestation at entry to prenatal care, alcohol drinking and smoking, time since and outcome of preceding pregnancy, surgery performed during pregnancy, anemia, and diagnoses of uterine abnormalities, sexually transmitted diseases, and urinary tract infections. We used proportional hazards analysis to evaluate associations for each subgroup of preterm delivery. The relative odds associated with a history of preterm delivery in the preceding pregnancy ranged from 3.1 for deliveries due to preterm labor or PROM to 6.2 for deliveries that occurred during 29-32 weeks; none of the other factors was consistently associated across the subgroups of preterm delivery. The paucity of associations is consistent with the conclusion of other investigators that most of the causes of preterm delivery are unknown.

Adolescent↗
PubMed1994

Antenatal hospitalization among enlisted servicewomen, 1987-1990.

OBJECTIVE: To describe the prevalence of, and indications for, antenatal hospitalization among women who delivered live and stillborn infants. METHODS: We reviewed the records of a cohort of 1825 black and white enlisted women who delivered from 1987-1990 at the four largest Army medical centers in the United States. Women with multiple gestations and those whose pregnancies ended before 20 weeks' gestation were excluded. Records of all women with preterm deliveries and a one-third sample of women with term deliveries were abstracted. RESULTS: Overall, 26.8 +/- 1.6% (mean +/- standard error) of the women were hospitalized antenatally. Of the estimated 702 antenatal hospitalizations, 44.0 +/- 3.4% were related to preterm labor, 10.3 +/- 1.9% to preeclampsia, 5.5 +/- 1.5% to hyperemesis, and 4.7 +/- 1.5% to urinary tract or kidney infection. The prevalence of hospitalization was lowest before 20 weeks (5.0 +/- 0.8%) and highest at 33-36 weeks (12.2 +/- 1.2%). Small and probably clinically insignificant differences between black and white women were noted in the overall prevalence of antenatal hospitalization and in the indications for hospitalization. CONCLUSION: As measured by hospitalization, severe antenatal morbidity is common in this population of healthy enlisted women.

Adolescent↗
PubMed1993

Angiopeptin inhibition of myointimal hyperplasia after balloon angioplasty of large arteries in hypercholesterolaemic rabbits.

1. Currently, a wide range of drugs is being evaluated for the ability to prevent the restenosis which frequently accompanies percutaneous transluminal coronary angioplasty. Patients undergoing angioplasty are generally hypercholesterolaemic and therefore the possibility that plasma lipids may compromise the efficacy of anti-restenotic drugs must be assessed. A promising drug in several clinical trials for the prevention of restenosis is angiopeptin, an octapeptide analogue of somatostatin that possesses a highly lipophilic terminal. 2. The effect of angiopeptin on myointimal hyperplasia was studied in a rabbit model of arterial balloon catheter injury where the rabbits were made hypercholesterolaemic by a 0.5% cholesterol diet. The degree of subsequent myointimal thickening was measured by morphometry. 3. Angiopeptin (20 micrograms day-1 kg-1) significantly inhibited myointimal thickening by an average of 47% in the infrarenal aorta and both the common and external iliac arteries in the presence of elevated plasma lipids concentrations. Low dose angiopeptin (2 micrograms day-1 kg-1) significantly inhibited myointimal thickening in the external iliac artery but not in the other two vessels. 4. Angiopeptin treatment (20 micrograms day-1 kg-1) did not significantly modify the plasma cholesterol, very-low-density lipoprotein, intermediate-sized low-density lipoprotein, low-density lipoprotein and high-density lipoprotein concentrations that were elevated by the 0.5% cholesterol diet. 5. We conclude that the inhibitory effect of angiopeptin is largely unaffected by elevated plasma lipid concentrations and that this drug did not modify plasma lipid concentrations in rabbits.

Angioplasty, Balloon↗
PubMed1993

Pregnancy planning and pre-conception counseling. The PRAMS Working Group.

OBJECTIVE: To estimate the percentage of women with one or more of four potentially modifiable risks who could have availed themselves of pre-conception counseling. METHODS: We defined pre-conception counseling to be consultation that occurs shortly before a couple attempts conception. Thus, we assumed that to obtain pre-conception counseling, a woman must plan her pregnancy. We used data from a population-based survey of 12,452 new mothers in four states who delivered babies during 1988-1990. Mothers were contacted 3-6 months after delivery and asked about pre-conception behaviors and the planning status of their pregnancies. We estimated the percentage of women who planned their pregnancies and had an indication for pre-conception counseling related to smoking, drinking, being underweight, or delaying initiation of prenatal care. RESULTS: State-specific response rates ranged from 68-84%. Sixty percent of mothers reported that their pregnancies were planned. In general, mothers with unintended pregnancies were more likely to have an indication for pre-conception counseling than mothers with planned pregnancies. Thirty-eight percent of all mothers planned their pregnancies and had one or more indications for pre-conception counseling. An additional 30% had one or more indications for counseling but did not have a planned pregnancy. CONCLUSIONS: Despite the limited range of indications for counseling that we considered, a substantial percentage of women potentially could have used counseling. A similar percentage of women could have benefited from family planning services.

Adult↗
PubMed1993

Preterm delivery among black and white enlisted women in the United States Army.

OBJECTIVE: To examine black-white differences in preterm delivery in a healthy population who had unrestricted access to prenatal care. METHODS: We conducted a retrospective cohort study of 842 black and 1026 white enlisted servicewomen who delivered a singleton infant of 20 or more weeks' gestation from July 1, 1987 through September 30, 1990 at four Army Medical Centers in the United States. Data were collected by reviewing maternal and newborn records. We used logistic and proportional hazards regression models to analyze outcomes defined by length of gestation, cause of preterm delivery, and jointly by length and cause. RESULTS: Black enlisted women had a cumulative probability of preterm delivery (13.5%) that was higher than that for white enlisted women (10.5%) (hazard ratio 1.31, 95% confidence interval [CI] 1.002-1.70). However, the ratio of black-to-white hazards was not uniform. Black-white differences were small and nonsignificant from 33-36 weeks' gestation, when most preterm deliveries occur. The differences were also small and nonsignificant for deliveries related to spontaneous rupture of membranes or idiopathic preterm labor, the most common causes of preterm delivery. The black-to-white hazard ratios were greatest for all deliveries before 33 weeks' gestation and for medically indicated preterm deliveries. CONCLUSIONS: Efforts to reduce black-white differences in preterm delivery must go beyond providing prenatal care and eliminating recreational drug use. Future studies should consider black-white differences in environments during the mother's own development and in psychosocial and physical stresses during pregnancy.

Adolescent↗
PubMed1992

Smoking, pregnancy, and source of prenatal care: results from the Pregnancy Risk Assessment Monitoring System. The Pregnancy Risk Assessment Monitoring System Working Group.

OBJECTIVE: To assess the impact of current smoking intervention efforts and to target future efforts by describing the relationships between maternal smoking, smoking cessation, and source of prenatal care. METHODS: We used population-based data from 6319 mothers who delivered live-born infants during 1988 and 1989 in Maine, Michigan, Oklahoma, and West Virginia. The number of women sampled per state ranged from 1490-2659; state-specific response rates ranged from 66-84%. Analysis weights adjusted for selection probability and non-response. RESULTS: The prevalences of maternal smoking before, during, and after pregnancy among women receiving publicly funded prenatal care were 2.3-3.4 times the comparable prevalences among privately insured women receiving prenatal care from private providers. Although many smokers reduced or quit smoking during pregnancy, most resumed or increased their smoking to nearly pre-pregnancy levels by 3-6 months postpartum. CONCLUSIONS: Interventions should target the very high levels of smoking among the 27% of women receiving publicly funded prenatal care. However, from a population perspective, the greatest potential for reduction in smoking is among patients of private providers, who care for 61% of pre-pregnancy smokers.

Female↗
PubMed1991

Another look at the black-white gap in gestation-specific perinatal mortality.

In the US, black infants born near or at term experience higher mortality than white infants. To extend our understanding of black-white differences in the relative advantages of growth (measured by birthweight) for gestational age, we compared race-specific rates of perinatal mortality by deviation in grams from the median birthweight for four categories of gestation (35-36, 37-38, 39-41, and 42-43 weeks). We also used race-specific standards to examine the difference between the median birthweight and the optimum birthweight (i.e. birthweight with the lowest mortality). The data, which were derived from vital records for singletons delivered in the US from 1983-1984, comprised 24,626 fetal and neonatal deaths among 5,157,197 white infants and 5973 fetal and neonatal deaths among 926,678 black infants. At all deviations from the median birthweight, black infants had relatively better survival at 35-36 weeks of gestation. This advantage was reversed among infants with gestations of 39-41 and 42-43 weeks. The optimum birthweight for black infants with gestations greater than or equal to 37 weeks was closer to their median birthweight than was that for white infants. For black infants with gestations of 39-41 weeks, the optimum birthweight was 187g (95% confidence interval (CI): 150-234) greater than the median birthweight (3289g); for comparable white infants the optimum birthweight was 397g (95% CI: 366-431) greater than the median birthweight (3487g). To reduce the black-white gap in perinatal mortality, we need a better understanding of aetiological relations between gestation, growth, and mortality.

Birth Weight↗